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https://issues.apache.org/jira/browse/BEAM-5063?focusedWorklogId=133720&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-133720
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ASF GitHub Bot logged work on BEAM-5063:
----------------------------------------
Author: ASF GitHub Bot
Created on: 10/Aug/18 17:48
Start Date: 10/Aug/18 17:48
Worklog Time Spent: 10m
Work Description: rangadi commented on a change in pull request #6178:
[BEAM-5063] Fix Watermark does not progress for low traffic streams
URL: https://github.com/apache/beam/pull/6178#discussion_r209332336
##########
File path:
sdks/java/io/kinesis/src/main/java/org/apache/beam/sdk/io/kinesis/KinesisWatermark.java
##########
@@ -0,0 +1,111 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.beam.sdk.io.kinesis;
+
+import java.util.function.BooleanSupplier;
+import org.apache.beam.sdk.transforms.Min;
+import org.apache.beam.sdk.util.MovingFunction;
+import org.joda.time.Duration;
+import org.joda.time.Instant;
+
+/** Keeps track of current watermark using {@link MovingFunction}. */
Review comment:
Would be nice have a short description aimed at end users about how
watermark progresses. As I understand, it would be something like : "on a topic
with steady traffic, it would around 'now - 1 minute', if the topic is mostly
idle it could be between 'now - 2 minutes' to 'now'". [ I have a comment below
about setting to to 'now' when shards are up to date].
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Issue Time Tracking
-------------------
Worklog Id: (was: 133720)
Time Spent: 1h 10m (was: 1h)
> Watermark does not progress for low traffic streams
> ---------------------------------------------------
>
> Key: BEAM-5063
> URL: https://issues.apache.org/jira/browse/BEAM-5063
> Project: Beam
> Issue Type: Bug
> Components: io-java-kinesis
> Affects Versions: 2.5.0
> Reporter: Krzysztof Trubalski
> Assignee: Jean-Baptiste Onofré
> Priority: Major
> Time Spent: 1h 10m
> Remaining Estimate: 0h
>
> We have a Dataflow Job copying data from multiple Kinesis streams into Big
> Query. Recently we have noticed that the watermark on one of the streams
> frequently gets stuck although data from that stream is still being processed
> (it progress only when the traffic increases or Dataflow autoscaling feature
> kicks in).
>
> Looking at the CloudWatch statistics for the affected stream, it has a
> really low traffic rate - only ~1 event every few minutes . After
> investigation and consulting the issue with Google's Dataflow Team, it looks
> like with such small amount of data on the stream, the function calculating
> the watermark in KinesisReader reports progress incorrectly.
>
> From my initial investigation, I suspect that the issue might be related to
> usage of MovingFunction in KinesisReader. In the current implementation, it
> covers 1 minute period of samples, since obtaining the min value flushes
> stale values, if the traffic is very low the following call to significance
> check always returns false (as it relies on the number of samples, and most
> of them were flushed by get() invocation).
>
>
>
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